A lot of people don’t know the real purpose of using shielding gas in welding. A large number of people never stop to ask or question the real reason why it is used in some processes and not in others. They just keep doing as they were taught or told and never attempt to learn about the subject. With this article, I hope I can give you guys the basics about using shielding gas in welding and why they are not used in some processes.
Most commonly MIG and TIG methods use shielding gas while stick welding does not. Shielding gas can be divided between inert and active and, can affect the quality of your welds so you should be careful about selecting the right combination. Using external gas is also one of the reasons why MIG and TIG methods are not recommended to be used in windy conditions.
EFFECT OF SHIELDING GAS ON WELDING
Contents
Knowing which type of shielding gas to use and when to use it can greatly affect the quality and cost of your weld. As you can probably tell, shielding gas can greatly influence both of these factors, before we talk about the different types of shielding gases and when to use them, it is important to know what they do.
The name probably gives it away, the shielding gas basically shields the molten weld or the weld pool from the impurities in the atmosphere like vapors and dust while also protects the weld from oxygenation. These impurities can make your final weld weak, decrease its durability and its corrosion tolerance. It can also lead to porous results and affect the geometrical features of the weld.
TYPES OF DIFFERENT SHIELDING GASES
Shielding gases can be divided into two major types when it comes to their chemical effect on the weld, inert or active. An inert gas as the name suggests will not interact with the molten weld but on the other hand, an active gas will actively interact with the weld pool. Some of the major ways it helps the process is in stabilizing the arc and making sure that there is a smooth transfer of material.
Some of the most common gases which are used as shielding gas are Argon, Helium, Carbon Dioxide, and Oxygen.
Argon is a type of inert gas which means it will not interact with the workpiece. It is one of the most commonly used gases in TIG welding. Argon does not lead to oxygenation or change the chemical composition of the final weld.
Helium is also a very popular welding gas which is used with both MIG and TIG welding process. It can be used just by itself and also in combination with Argon. Some of the advantages of helium over argon is the better welding speed and better side penetration.
Carbon Dioxide and Oxygen are mostly used in combination with other gases as the oxygenating component in the mixture. Some of the most common uses of these gases are arc stabilization and smoother transmission of material.
I have a whole article about picking the right shielding gas for MIG welding here.
APPLICATION ISSUES OF SHIELDING GASES
There are some factors that can limit the usage of shielding gases for welds, some of these factors can be controlled while others cannot. The first factor is the cost related to the weld. the equipment which is used for gas delivery adds some extra cost to the bottom line. While gases like argon can be a bit expensive to be used by everyone.
Most of the processes which use shielding gas have to be used indoors so that the gas doesn’t dissipate because of environmental factors like wind. This limits the usability of shielding gases for welding
DOES STICK WELDING REQUIRE GAS (WHY NOT)
One of the reasons stick welding is popular especially among beginners and hobbyists is its lack of shielding gas usage. You probably know this but let me just repeat it for the sake of clarity. Stick welding uses a flux coated rod called an electrode which melts along with the metal to form the weld pool. This flux coat emits vapors and gases which does the job of protecting the weld pool. This makes the use of shielding gas pointless.
CAN YOU STICK WELD IN THE WIND
As I mentioned before, one of the advantages of stick welding is its versatility. Although MIG and TIG have other advantages, one shortfall is that they cannot be used during windy conditions. On the other hand, stick welding can be used in a lot more varied conditions.
One of the reasons for this is that the shielding gas may get dissipated if the wind is too strong and this may result in bad quality welds and may cause porosity. As the flux is present on the electrode itself, windy conditions don’t really affect the weld. But make sure to pause the welding if the conditions become too extreme.
I don’t know the authenticity of these numbers, but a lot of blogs state that you should stop MIG and TIG welding when the wind is above 5mph. while stick welding can be used perfectly till about 35mps.
WHAT WELDING METHODS REQUIRE SHIELDING GAS? (MIG,TIG)
As I said earlier, some methods do not require shielding gases at all while some methods require them. The processes which do not require them to create some sort of their own shielding system involves slag formation and gases from the chemical reactions in the arc.
Some of the processes which do not require shielding gas are, Shielded Metal Arc welding (SMAW/stick), Self-Shielded Flux-cored arc welding (FCAW-S), and Submerged Arc welding.
On the other hand, some of the most popular processes which do require the use of shielding gas are, Gas Tungsten Arc Welding (GTAW/TIG), Gas Metal Arc Welding (GMAW/MIG), Metal Cored Arc Welding (GMAW-C), Gas Shielded, Flux Cored Arc Welding (FCAW-G).
FREQUENTLY ASKED QUESTIONS:
The uses and types of shielding gases is a vast topic and can take a lot of time and experience to understand everything in depth. While I do recommend that you should read as much as possible, it is important to clear any questions related to the basics of it all. I will try to address some of the most common queries that people have below, hope it helps.
This answer depends on a lot of factors like the metal you are working on, the electrode you are using or the wire in case of MIG. But a lot of people do seem to think that in general for an enthusiast, stick welding will provide more penetration and a stronger weld.
As I said earlier in the articles, MIG and TIG welding processes are the major techniques that use additional gas for working. On the other hand Stick welding does not usually require any external gas to work.
MIG welding is considered by many to be much easier for a beginner to learn when compared to stick welding. But the drawback for beginners is the higher cost related to setting up a MIG welding workstation. There are some factors in stick welding which can be harder to grasp in the beginning like striking an arc and maintaining proper arc length.
CONCLUSION
There is a lot of information available on this subject which you can further read to expand your knowledge. Using the right shielding gas combinations can elevate your welding experience and quality. To sum it all up, keep a few things in mind. MIG and TIG are the major welding processes that require shielding gas. Shielding gases can be divided into inert and active gases and each gas has a specific use over the others. Also, keep in mind that processes that use shielding gas cannot be used in windy conditions which can limit its real life application.